IA Psych Juris common mistakes
IA Psych Juris · Understand the traps and how to avoid them.
When asked who bears the burden of proof on competency to stand trial, the candidate answers 'the defense' because the defense raised the issue, or answers 'beyond a reasonable doubt' because the setting is criminal.
Candidates generalize from ordinary criminal procedure, where the party raising a motion carries the burden and the standard is high. They do not hold separately the rule that once a bona fide doubt about competency is raised, the prosecution must establish competency by a preponderance of the evidence (Dusky/Cooper v. Oklahoma line), and they conflate this with the insanity defense burden, which in most jurisdictions falls on the defense.
What to do instead
Build a one-page matrix with columns for competency to stand trial, insanity at time of offense, and civil commitment, and rows for who raises the issue, who bears the burden, the standard of proof, and the legal consequence of a finding. Drill the matrix until the three rows are automatic, and rehearse the phrase 'preponderance, on the prosecution' specifically for Dusky competency.
The candidate treats a defendant who is malingering or exaggerating symptoms as automatically incompetent, or conversely treats any cooperative presentation as genuine without testing effort and feigning.
Candidates collapse the clinical question (does the person have a mental disorder?) with the legal question (can the person rationally understand the proceedings and assist counsel?). They also over-rely on interview impression and are unaware that feigning instruments are screening tools with imperfect specificity, not lie detectors.
What to do instead
Practice writing conclusions in the two-step Dusky framework: first state the diagnosis and symptom validity findings, then state the functional legal capacities and the reasoning linking them. Always administer at least one validated performance validity or feigning measure (e.g., TOMM, SIMS, or an embedded validity index) and interpret it as one data point, explicitly noting base rates and the possibility of false positives before drawing a malingering conclusion.
When selecting a risk instrument, the candidate picks the tool with the highest reported AUC in the literature without checking whether its validation samples, setting, gender, age, or cultural group match the evaluee.
Candidates memorize instrument names and headline statistics from study guides and treat predictive accuracy as a fixed property of the test. They forget that AUCs are sample-dependent and that a tool validated on civilly committed adult males may perform poorly on a female pretrial defendant or an adolescent.
What to do instead
For every instrument you cite, be able to state its intended population, its validation settings, its item structure (static versus dynamic), and at least one limitation. In answers, name the instrument plus the matching rationale plus the caveat, e.g., 'HCR-20 V3 because it captures dynamic, treatment-relevant factors in an inpatient setting, though it requires structured professional judgment rather than actuarial cutoffs.'
The candidate reports an actuarial risk score as if it were an individual prediction, e.g., 'this offender has a 38% chance of reoffending,' and omits confidence intervals, base rates, and the structured professional judgment framing.
Candidates confuse group base rates with individual probability and are trained in clinical rather than forensic reporting habits. They also fear appearing equivocal, so they overstate precision to seem decisive, which is exactly the error courts scrutinize.
What to do instead
Adopt a fixed reporting template: state the instrument, the score, the normative group it was derived from, the associated recidivism rate for that group, and an explicit statement that this is a group estimate not an individual prediction. Then give a risk level (low/moderate/high) with the factors driving it and the management implications. Rehearse this template until it is the default in every risk question.
The candidate agrees to conduct a child custody evaluation when they have previously provided therapy to one parent or the child, or accepts a referral from the parent's attorney who is also a close friend, and does not identify the conflict.
Candidates underestimate how strictly the dual-role prohibition applies in forensic family work. They reason that prior therapy gives them useful information and that a personal relationship is harmless, mirroring norms from clinical practice where multiple relationships are sometimes tolerated.
What to do instead
Memorize the bright-line rule: never serve as both treating clinician and forensic evaluator in the same matter, and decline or disclose any relationship that a reasonable observer could see as compromising neutrality. Practice the script for declining or referring out, and in exam answers always name the specific guideline (e.g., APA Specialty Guidelines for Forensic Psychology on multiple relationships and impartiality) rather than saying only 'avoid conflicts.'
The candidate describes the evaluation as serving the court or the retaining attorney and writes conclusions that advocate for the retaining party's position, or accepts a contingency fee.
Candidates carry over the clinical mindset of helping the patient and the business norm of pleasing the client. In forensic work the client is the court or the retaining entity, but the obligation of impartiality runs to the legal decision-maker, and this distinction is easy to lose when the attorney is paying.
What to do instead
State the role explicitly at the start of every answer: 'The evaluator's client is the retaining attorney or court, but the obligation is to provide impartial data to the legal decision-maker.' Name prohibited practices directly: contingent fees, outcome-dependent contracts, and ghostwritten reports. When a question describes attorney pressure, the correct answer is to document the pressure, maintain the independent opinion, and if necessary withdraw.
The candidate answers a civil commitment question about sexually violent predator statutes by applying the criminal standard of proof or by assuming the person must be released at the end of the prison term.
Candidates map the criminal framework onto a civil proceeding because the person is incarcerated and the conduct was criminal. They miss that SVP commitment is civil, that it typically requires a finding of a mental abnormality or personality disorder plus likely serious difficulty controlling behavior, and that the standard is usually clear and convincing evidence rather than beyond a reasonable doubt.
What to do instead
Build a comparison table of SVP civil commitment versus criminal sentencing: legal authority, standard of proof, required findings, role of the evaluator, and the treatment of 'volitional capacity' language from Kansas v. Hendricks and Kansas v. Crane. Practice explaining why commitment after sentence completion is constitutional when it is civil and preventive rather than punitive.
The candidate writes a personal injury report that states a diagnosis and prognosis without addressing causation, malingering, and the distinction between the evaluator's clinical opinion and the ultimate legal question.
Candidates import the treatment report format, which assumes the patient is truthful and focuses on diagnosis and plan. In civil forensic work the central questions are whether the claimed condition was caused by the event, whether it is exaggerated, and what the law requires, and the evaluator must address these explicitly rather than leave them implicit.
What to do instead
Use a causation-focused outline: pre-existing conditions, temporal relationship, mechanism of injury, consistency with known base rates, and validity testing results. Include a section on effort and symptom validity with the measures used. End with a clearly labeled opinion that answers the referral question in behavioral terms and states whether the ultimate legal issue is being addressed or deferred.
The candidate answers police psychology questions by describing fitness-for-duty or hostage-negotiation consultation as ordinary therapy for officers, or fails to distinguish the agency as client from the officer as client.
Candidates lack exposure to public safety psychology and default to clinical assumptions. They do not know that fitness-for-duty evaluations, critical incident debriefings, and pre-employment psychological screening each have different clients, different consent rules, and different disclosure obligations.
What to do instead
Create a service-by-service table for police and public safety psychology: pre-employment screening, fitness for duty, critical incident response, and operational consultation, with columns for who is the client, what consent and notification apply, and what the evaluator may disclose. Note that in fitness-for-duty work the agency is the client and the officer must be told this in advance.
The candidate selects a forensic instrument because it is popular or because a colleague uses it, without being able to state its reliability, validity, normative sample, and the legal standard for admissibility in the relevant jurisdiction.
Candidates study test names rather than the psychometric and legal criteria for test selection, and they do not connect instrument choice to the Daubert or Frye framework that governs expert testimony. They also assume that a test used in one jurisdiction is admissible everywhere.
What to do instead
For each major instrument in your study set, write four lines: what it measures, its reported reliability and validity, its normative sample, and one criticism. Then practice linking that to admissibility: general acceptance, peer review, known error rate, and testability. In answers, justify the instrument choice with those criteria rather than with popularity or habit.